Pituitary

Question 1

What are the arteries right lateral to pituitary gland?

Answer 1

Internal carotid arteries

Question 2

What is a physically active hormone produced from pituitary? (that does not have to act on something else to produce effect)

Answer 2

Prolactin

Its secretion is consistently inhibited (tonic inhibition) by hypothalamic dopamine

Question 3

What does baseline pituitary function test involve?

Answer 3

9am cortisol
TSH, free thyroxine, free T3
Prolactin
LH/FSH (oestradiol for F, 9 am testosterone for M) - LH and FSH would be a bit high in post-menopausal F
IGF-1 (GH surrogate)

Urine and osmolality

Question 4

What is a dynamic test for ACTH/cortisol and how does it work?

Answer 4

For chronic ACTH deficiency, adrenal gland would shrink, hence upon synthetic ACTH (synacthen) injection, cortisol response would be low on observation

But for acute adrenal damage, 9am cortisol is more suitable

Question 4

What does hypopituitarism lead to?

Answer 4

GHD - growth failure in kids
TSH - secondary hypothroidism
LH/FSH - hypogonadropic hypogonadism
ACTH - secondary hypoadrenal

ADH deficiency - arginine vasopressin deficiency (diabetes insipidus) *might be a serious condition

Question 5

How are hormones replaced?

Answer 5

Hydrocortisone - 2 to 3 times a day
Thyroxine
Sex steroids
GH (SC injection)
ADH - Desmopressin tablets/nasospray

Question 5

What are causes of hypopituitarism?

Answer 5

Pituitary tumours
Non-pituitary brain tumours
Brain injury/damage
Iatrogenic
Granulomatous disease

Question 6

Presentation of macro non-functioning pituitary adenomas?

Answer 6

Function: Hypopituitarism/hyperprolactinaemia

ACTH deficiency
TSH deficiency
LH/FSH deficiency hypothyroidism
GH deficiency
raised prolactin

Size:
Compression of optic chiasm or cavernous sinuses

Question 7

How to manage macro non-functioning pituitary adenomas?

Answer 7

Trans-sphenoidal surgical resection

Question 8

Prolactinoma

Answer 8

Commonest functioning pituitary tumour
Common in young woman (but overall M=F)
Infertility

1st-line Mx: Cabergoline (dopamine agonists)
*Would lead to effective shrinkage of giant prolactinomas (the shrinkage may also cause some effects like CSF leakage which need to be acted on)

Question 9

Raised prolactin can be due to various reasons (unless extremely extremely raised, which would be prolactinoma)

Answer 9

Pharmacological reasons might be intake of dopamine receptor inhibitors

Question 10

What are the range of symptoms of acromegaly?

Answer 10

Thickened soft tissues
Obstructive sleep apnoea
Arthropathy
Cardiovascular morbidity
etc

Question 11

Cushing’s syndrome

Answer 11

Pituitary (majority) = Cushing’s DISEASE (65% of all Cushing’s)

Cortisol secreting adrenal tumour (independent of ACTH)
Ectopic ACTH production (usually related to cancer)

These need to be differentiated from physiological hypercortisolaemia

Question 12

What are the features of excess cortisol/mineralocorticoid/androgen?

Answer 12

Excess cortisol
- protein loss
*myopathy; wasting
*osteoporosis;fracture

Question 13

Screening of Cushing’s

Answer 13

*Overnight dexamethasone suppression test (oral)
*Urinary free cortisol
*Diurnal cortisol variation
(loss of diurnal variation suspicious of Cushing’s)

Question 14

Diagnostic test of Cushing’s

Answer 14

Low dexamethasone suppression test dose (48 hr test starting from 9am)

Once confirmed from this - measure ACTH to check if it is dependent of it

ACTH undetectable/low – ACTH independent
ACTH normal/high – ACTH dependent

Question 15

Apoplexy management

Answer 15

Pituitary function (for cortisol, just check point value)
MRI
Formal visual field assessment
Treat acute hormone deficits *eg emergency steroid dosing
Conservative vs surgical management dependent on clinical features

Question 16

Hypophysitis

Answer 16

Inflammation of the pituitary gland (more commonly now as more monoclonal antibodies are used to treat cancer - a side effect)

Autoimmune
Systemic inflammation
Medication
Infection

Question 17

Arginine vasopressin deficiency

Answer 17

This is due to deficiency in production of AVP in posterior pituitary

AVP resistance would be a nephrogenic problem
- Differentiate by doing water deprivation test using desmopressin